// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/hyphenation/hyphenation_impl.h"

#include <algorithm>
#include <map>
#include <utility>

#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/timer/elapsed_timer.h"
#include "mojo/public/cpp/bindings/strong_binding.h"

namespace {

using DictionaryFileMap = std::unordered_map<std::string, base::File>;

bool IsValidLocale(const std::string& locale)
{
    return std::all_of(locale.cbegin(), locale.cend(), [](const char ch) {
        return base::IsAsciiAlpha(ch) || base::IsAsciiDigit(ch) || ch == '-';
    });
}

base::File GetDictionaryFile(const std::string& locale)
{
    // Keep Files open in the cache for subsequent calls.
    CR_DEFINE_STATIC_LOCAL(DictionaryFileMap, cache, ());

    const auto& it = cache.find(locale);
    if (it != cache.end())
        return it->second.Duplicate();
    const auto& inserted = cache.insert(std::make_pair(locale, base::File()));
    base::File& file = inserted.first->second;
    DCHECK(!file.IsValid());

#if defined(OS_ANDROID)
    base::FilePath dir("/system/usr/hyphen-data");
#else
#error "This configuration is not supported."
#endif
    std::string filename = base::StringPrintf("hyph-%s.hyb", locale.c_str());
    base::FilePath path = dir.AppendASCII(filename);
    base::ElapsedTimer timer;
    file.Initialize(path, base::File::FLAG_OPEN | base::File::FLAG_READ);
    UMA_HISTOGRAM_TIMES("Hyphenation.Open.File", timer.Elapsed());
    return file.Duplicate();
}

} // namespace

namespace hyphenation {

HyphenationImpl::HyphenationImpl() { }

HyphenationImpl::~HyphenationImpl() { }

// static
void HyphenationImpl::Create(blink::mojom::HyphenationRequest request)
{
    mojo::MakeStrongBinding(base::MakeUnique<HyphenationImpl>(),
        std::move(request));
}

void HyphenationImpl::OpenDictionary(const std::string& locale,
    const OpenDictionaryCallback& callback)
{
    if (IsValidLocale(locale))
        callback.Run(GetDictionaryFile(locale));
    else
        callback.Run(base::File());
}

} // namespace hyphenation
